Watercraft, especially those of the type known as personal watercraft, are commonly powered by internal combustion engines positioned within their hulls. These engines are arranged to drive a water propulsion device for propelling the craft.
As is well known, it is undesirable to allow water to enter the intake system of such an engine, as the water may foul the combustion chamber(s) and cause the engine to stall or stop. In addition, the water may be passed through the engine to a catalyst positioned in the exhaust system, damaging it as well.
It is common for the air intake to be positioned at the top of the engine and may open upwardly. In the watercraft setting, this is undesirable, since water may flow directly into the intake and down into the engine. Thus, as one method for reducing the opportunity for water to enter the intake system, the air intake opening leading to the engine may be positioned within an air box, with air supplied to the air box through an inlet or pipe.
A problem also exists with this arrangement relating to the nature of personal watercraft. This type of watercraft is often capsized, laying on either side or completely upside down. When this occurs, water in the engine compartment or elsewhere may then still enter the air box or air intake to the engine.
In order to solve the above-stated problems, an intake box may be provided, with the opening to the air intake pipe positioned within the box and above a lower surface of the box. The box is also preferably large, so that water does not fill the box and flow up over the intake pipe and into the engine.
A problem with the large intake box, however, is that it interferes with the choke and throttle control of the intake system. In particular, these engines typically have positioned in each intake passage a throttle plate and a choke plate for controlling the flow of air through the intake passage. The choke plate is positioned near the top of the intake passage. The position of the choke plate requires that an external choke control also be positioned near the top end of the intake passage, but this interferes with the use of a large intake box, which occupies the same space.
In addition, so that the throttle and choke controls are easy to operate, a long control lever is utilized. The long lever associated with these controls also interferes with the use of a large intake box as is desired to prevent water entry into the engine through the intake system.
An intake control mechanism for an air intake of an engine of the type utilized to power a watercraft and which allows for use of a large intake box, is desired.